Seismic behavior of cold-formed steel framed multi-panel and two-story shear walls

This paper presents an experimental investigation on the seismic behavior of cold-formed steel (CFS) shear wall systems. Two sets of cyclic lateral loading tests were conducted on OSB sheathed CFS shear wall specimens. The first part of the study deals with walls constructed by connecting multiple individual wall panels with different connection methods. Focus of the second part is the lateral load response of two-story shear walls with different framing details between wall panels in neighboring floors. In both parts, the behavior of wall panels was examined with combinations of one side sheathing and a coarse fastener layout, as well as double-side sheathing and a dense fastener layout. For the multi-panel shear walls, eight full-scale specimens were tested, featuring varying configurations of CFS framing and OSB sheathing. The experiments indicate that the use of different connection details between individual wall segments does not cause any appreciable difference in wall response. Significant excessive base slip was observed in longer walls with double-side sheathing due to increased shear force demand at the base, highlighting the importance of adequate fastener layout. In the investigation of two-story shear walls, eight specimens were tested. Platform and ledger framing details were explored, each with different methods of connecting wall panels between floors. The results demonstrated the influence of framing detail on the overall behavior and failure mechanisms of the shear walls. Notably, the presence of additional OSB sheathing panels between floors enhanced the load capacity and stiffness of the specimens, mitigating damage to CFS members within the connection region. Based on the experimental findings, practical recommendations were presented for multi-panel walls and interaction between wall panels and floor support system in multi-story CFS construction.